Political tensions are rising in Zimbabwe, where police cancelled a Movement for Democratic Change rally, while Prime Minister Morgan Tsvangirai made an unscheduled weekend visit to South African President Jacob Zuma before a regional security meeting this week. MDC officials say they expect more senior members to be arrested this week.

Zimbabwe’s pro-ZANU-PF Sunday Mail newspaper says MDC chairman and former speaker of parliament Lovemore Moyo will be arrested soon. The newspaper says papers have been drawn up by the attorney-general’s office to charge him with contempt of court, for allegedly criticizing the judiciary.

Moyo was recently stripped of his position as speaker by the Supreme Court, which cited irregularities when he was elected to the post two years ago.

Security sources in Harare say Mr. Tsvangirai also fears arrest as he too criticized the Supreme Court after MDC deputy treasurer Elton Mangoma, who is also energy minister in the inclusive government, was arrested three weeks ago.

Mr. Tsvangirai followed those off-the-cuff remarks with what many analysts say appeared to be an apology for criticizing the judges, who many legal analysts consider overwhelmingly loyal to ZANU-PF and President Robert Mugabe.

Several other leading MDC personalities are either in hiding in Zimbabwe or are keeping a low profile.

The MDC won control of parliament in 2008, but the party says Mr. Mugabe and ZANU-PF have been using the police and judiciary to harass MDC leaders and negate its clout in the coalition government.

The party says men dressed in Zimbabwe Republic Police uniforms and singing ZANU-PF songs tried to force their way into the MDC's central headquarters Saturday in Harare. It says the men were repelled by MDC security officials.

That same day, the pro-ZANU-PF police told MDC it could not hold a rally scheduled for Sunday. The rally was supposed to replace one banned last weekend.

Mobile phones for the Zimbabwe Republic Police were turned off and there was no one answering telephones at police headquarters in Harare to explain why the rally was banned.

Meanwhile, teachers in several high-density suburbs around Harare say militant ZANU-PF loyalists have forced them to sign a ZANU-PF-designed petition protesting Western financial and travel sanctions against most ZANU-PF leaders and a few state companies.

Mr. Tsvangirai went to see Mr. Zuma at his traditional home in South Africa's rural KwaZulu Natal province on Saturday to brief him on the latest developments and rise in political temperature.

Mr. Tsvangirai’s spokesman, Luke Tamborinyika, said the prime minister also intended to visit leaders in Namibia, Tanzania and the Democratic Republic of Congo before a regional security meeting Thursday in Zambia's capital. The regional Southern African Development Community oversees the political agreement that led to Zimbabwe’s inclusive government two years ago.

The MDC says it hopes outstanding issues of the political agreement and the increasing political clampdown on their party will be high on the SADC's agenda.